Meteoroid impacts on spacecraft: sporadics, streams, and the 1999 Leonids

This paper considers impact effects such as penetration damage and plasma g eneration on satellites in Low Earth and Geostationary orbits. We character ise the spacecraft impact damage for the normal sporadic background and the annual meteoroid showers, and, especially consider the quantitative effect s which would occur should the 1999 apparition of the Leonids reach 'storm conditions'. In this case, the meteoroid shower has the damage potential wh ich could exceed the sporadic meteoroid background by several orders of mag nitude at peak. Impact velocities are considered and formulae for penetrati on, or, plasma charge production are presented. It is found that the Leonid s exceed any other stream in terms of plasma current generation even under normal 'quiescent' conditions. Due to the flux enhancement associated with a storm condition, spacecraft could suffer up to one year's worth of normal impact damage, with a few spacecraft suffering potentially catastrophic pl asma discharge events, and with the largest likely impact being able to pen etrate of order 1 cm of solid aluminium. (C) 1999 Elsevier Science Ltd. All rights reserved.